The Convent of Christ, with its Templar round church and Manueline window, deserves at least two to three hours, and entry is paid. The climb from the town to the convent is steep, on foot or by car. In town, Praça da República and the banks of the Nabão fill the rest of the day. The journey is one of the longest on this list, so leave early.
For a shorter outing, try Sintra: palaces and hills. For the following day in the city, the Lisbon in 1 day itinerary is a good start. Pair it with a stroll through Alfama. See other trips that go to Tomar.
Independent itineraries to do on your own. We do not sell tours, recommend tour operators or use affiliate links. Check timetables, tickets and access with official sources before you set off.